1. Field of the Invention
The present invention relates to a lamp driving device with an open voltage control and, more particularly, to a lamp driving device using a current detector to detect an operation of the lamp and stopping the operation of the lamp when it detects that the lamp circuit has opened abnormally.
2. Description of the Prior Art
Please refer to FIG. 1 for an implementation view of a prior art lamp driving device with an open voltage control. As shown in the figure, the lamp driving device with an open voltage control 1 uses a DC power source 11 to provide a DC signal to a square wave switch 12, the square wave switch 12 provides a square wave signal to an LC resonant circuit 14, and then the LC resonant circuit 14 provides a sinusoidal wave signal to a driver transformer 13 for the driver transformer 13 to drive a lamp 15. With this structure, it is common to set two capacitive elements 16 between a secondary side of the driver transformer 13 and the lamp 15, and to use a voltage dividing scheme to feedback a control signal to a square wave controller 17 for overvoltage protection. Although the above mechanism can provide overvoltage protection, it still presents some shortcomings such as:                1. The prior art technique uses capacitors to divide voltage so as to achieve the above object, however, since high voltage capacitors cost more than ordinary capacitors, they tend to increase the total cost of the lamp driving device.        2. In the prior art structure, the choice of the capacitive elements can greatly affect the stability of the overall lamp driving device.        
Therefore, it is desirable to overcome these shortcomings with the above-mentioned traditional lamp driving device.
In view of the above-described deficiencies of traditional lamp driving device, after years of constant effort in research, the inventor of this invention has consequently developed a new lamp driving device with an open voltage control described in the present invention.